Could you expand on the bad flow parts a bit? I know the bit on top of the demolished building (before sliding down the demolisher's crane) is slightly awkward, and I regret not making that more smooth (I tried to put it in mostly to give Dustworth a bit of competitive edge here, but it might not have been the best of ideas). Anything specific I need to avoid on future maps?

Well, losing flow usually happens when you have to fight an enemy right after a slope (or boosts in general) like the first enemy in this map.
The problem here is not that there is an enemy but that you can't jump to avoid losing speed. You have to attack it from the ground which causes your character to stop.

The second spot is the bridge. It's well done but the "dust" is placed to high on the right side of it. Hard to explain that. But in fact you gotta break in the air to get that. This is only bad for Score-Runs of course.

The third thing is the camera at one point.
When you go for a Time-Run you can' see the small slope (right in front of the first enemy).

That's all for now.
Sorry to be that critical. I am well known for that in other games, too. ;)
Your GFX looks awesome by the way. Wanna do it for my maps? xD

There's always a manual download (you can put the file in steam/steamapps/username/common/dustforce/levels), or you should set your Dustforce to Run as Administrator. There's a few threads on both the Steam Forums and the Reddit if you need any more help.

Two words: That drawbridge. Not to mention the flow. You move so swiftly through this level that it's hard to take in all the sights. Even with the very first run, I could tell how much work you put into the scenery. Keep up the good work!